An arrangement in which, in order to determine the timing of changing engine oil of an automobile engine, an oil deterioration sensor for detecting the degree of deterioration of engine oil based on the pH value is provided in a bottom part of an oil pan is known from Patent Publication 1 below. This oil deterioration sensor includes a sensing part housing a sensing element in the interior and a mounting part supporting the sensing part, and the mounting part is fixed to the bottom part of the oil pan by inserting the sensing part upwardly from an opening formed in the bottom part of the oil pan.
Furthermore, an arrangement in which, in order to suppress disturbance of the liquid surface of engine oil stored in the interior of an engine oil pan, a baffle plate is provided above the engine oil is known from Patent Publication 2 below.
Patent Publication 1: Japanese Patent Application Laid-open No. 2003-83935
Patent Publication 2: Japanese Patent Application Laid-open No. 11-30115